The present invention relates to an improved heat sink for use with electronic circuitry.
It is often necessary to achieve dissipation of undesired heat evolved in electronic circuitry. This has been accomplished by use of heat sinks made in a wide assortment of shapes and sizes. Such sinks generally include a metal base closely associated with the electronic part producing the undesired heat, and numerous cooling fins extending therefrom, generally of the same material as that of the base. In the past, relatively large one-piece heat sinks, of the base plate-cooling fin type, have been produced by casting or machining metal into a particular shape and size needed.
With the advent of miniaturized electronic circuitry, with components more densely packed in smaller volumes, it has become necessary to develop heat sinks which are both sufficiently small to conform to the size constraints accompanying miniaturization, and capable of carrying off adequate amounts of heat. Since large accumulation of heat is produced in a small region as a result of the densely packed circuitry, the requirements for adequate heat dissipation therefrom are difficult to meet.
Relatively small heat sinks have generally been made by forming a base plate, and then soldering or brazing independently fabricated metal cooling fins to the base. This method of assembly is costly and becomes more difficult as smaller heat sink sizes are contemplated. Moreover, the utilization of a base plate, separate from cooling fins, reduces the efficiency of heat dissipation by the heat sink, since the heat is not transmitted directly from the base plate to the cooling fin, but must first traverse a brazed or soldered joint which joins the two components, and may offer increased impedance to heat flow. Such diminished heat conductivity of course reduces the efficicacy of the heat sink.
The present invention is intended to obviate these disadvantages.